Electrode for active oxygen species and sensor using the electrode

Abstract

An electrode for active oxygen species comprising a conductive component with a polymer membrane of a metal porphyrin complex formed on the surface is disclosed. The electrode for active oxygen species can detect active oxygen species such as superoxide anion radicals, hydrogen peroxide, and .OH and other active radical species (NO, ONOO—, etc.) in any environment including in vivo environment as well as in vitro environment. The electrode thus can be used for specifying various diseases and examining active oxygen species in food or in water such as tap water and sewage water.

1 . (Deleted)  
     
     
         2 . An electrode for active oxygen species comprising a conductive component with a polymer membrane of a metal porphyrin complex shown by the following formula (I) or (II) formed on the surface,  
       
         
           
           
               
               
           
         
       
       wherein M is a metal selected from the group consisting of iron, manganese, cobalt, chromium, and iridium, at least one of the four Rs is a group selected from the group consisting of a thiofuryl group, pyrrolyl group, furyl group, mercaptophenyl group, and aminophenyl group, and the other Rs represent any one of these groups, an alkyl group, an aryl group, or hydrogen,  
       
         
           
           
               
               
           
         
       
       wherein M and R are the same as defined above, at least one of the two Ls is a nitrogen-containing axial ligand such as  5 imidazole and its derivative, pyridine and its derivative, aniline and its derivative, histidine and its derivative, and trimethylamine and its derivative, a sulfur-containing axial ligand such as thiophenol and its derivative, cysteine and its derivative, and methionine and its derivative, or an oxygen-containing axial ligand such as benzoic acid and its derivative, acetic acid and its derivative, phenol and its derivative, aliphatic alcohol and its derivative, and water, and the other L is any one of these axial ligands or a group without a ligand.  
     
     
         3 . The electrode according to  claim 2 , wherein the porphyrin compound forming the metal porphyrin complex is selected from the group consisting of 
 5,10,15,20-tetrakis(2-thiofuryl)porphyrin,    5,10,15,20-tetrakis(3-thiofuryl)porphyrin,    5,10,15,20-tetrakis(2-pyrrolyl)porphyrin,    5,10,15,20-tetrakis(3-pyrrolyl)porphyrin,    5,10,15,20-tetrakis(2-furyl)porphyrin,    5,10,15,20-tetrakis(3-furyl)porphyrin,    5,10,15,20-tetrakis(2-mercaptophenyl)porphyrin,    5,10,15,20-tetrakis(3-mercaptophenyl)porphyrin,    5,10,15,20-tetrakis( 4 -mercaptophenyl)porphyrin,    5,10,15,20-tetrakis(2-aminophenyl)porphyrin,    5,10,15,20-tetrakis(3-aminophenyl)porphyrin,    5,10,15,20-tetrakis(4-aminophenyl)porphyrin,    [5,10,15-tris(2-thiofuryl)-20-mono(phenyl)]porphyrin,    [5,10,15-tris(3-thiofuryl)-20-mono(phenyl)]porphyrin,    [5,10-bis(2-thiofuryl)-15,20-di(phenyl)]porphyrin,    [5,10-bis(3-thiofuryl)-15,20-di(phenyl)]porphyrin,    [5,15-bis(2-thiofuryl)-10,20-di(phenyl)]porphyrin,    [5,15-bis(3-thiofuryl)-10,20-di(phenyl)]porphyrin,    [5-mono(2-thiofuryl)-10,15,20-tri(phenyl)]porphyrin, and    [5-mono(3-thiofuryl)-10,15,20-tri(phenyl)]porphyrin.    
     
     
         4 . (Deleted)  
     
     
         5 . (Deleted)  
     
     
         6 . (Deleted)  
     
     
         7 . (Deleted)  
     
     
         8 . The electrode according to  claim 2  or claim  3 , wherein the conductive component is inserted into a small tube prepared from an electrical insulating material, the outside of this small tube is covered with a material acting as a counter electrode such as a metal to form a counter electrode, a metal porphyrin polymer membrane is formed on the tip of the conductive component, and the electrode has a needle-like shape.  
     
     
         9 . The electrode according to  claim 2  or  claim 3 , wherein the conductive component is inserted into an electrical insulating material, the electrical insulating material is placed in a counter electrode material, the resulting counter electrode material is housed in an electrical insulating material, of which the outside is covered with a material acting as a ground, a metal porphyrin polymer membrane is formed on the tip of the conductive component, and the electrode has a needle-like shape.  
     
     
         10 . The electrode according to any one of claims  2 ,  3 ,  8 , and  9 , used for measuring superoxide anion radicals.  
     
     
         11 . A sensor for measuring the concentration of active oxygen species comprising an electrode for active oxygen species comprising a conductive component with a polymer membrane of a metal porphyrin complex shown by the following formula (I) or (II) formed on the surface, a counter electrode, and a reference electrode,  
       
         
           
           
               
               
           
         
       
       wherein M is a metal selected from the group consisting of iron, manganese, cobalt, chromium, and iridium, at least one of the four Rs is a group selected from the group consisting of a thiofuryl group, pyrrolyl group, furyl group, mercaptophenyl group, and aminophenyl group, and the other Rs represent any one of these groups, an alkyl group, an aryl group, or hydrogen,  
       
         
           
           
               
               
           
         
       
       wherein M and R are the same as defined above, at least one of the two Ls is a nitrogen-containing axial ligand such as imidazole and its derivative, pyridine and its derivative, aniline and its derivative, histidine and its derivative, and trimethylamine and its derivative, a sulfur-containing axial ligand such as thiophenol and its derivative, cysteine and its derivative, and methionine and its derivative, or an oxygen-containing axial ligand such as benzoic acid and its derivative, acetic acid and its derivative, phenol and its derivative, aliphatic alcohol and its derivative, and water, and the other L is any one of these axial ligands or a group without a ligand.  
     
     
         12 . The sensor according to  claim 11 , wherein the porphyrin compound forming the metal porphyrin complex is selected from the group consisting of 
 5,10,15,20-tetrakis(2-thiofuryl)porphyrin,    5,10,15,20-tetrakis(3-thiofuryl)porphyrin,    5,10,15,20-tetrakis(2-pyrrolyl)porphyrin,    5,10,15,20-tetrakis(3-pyrrolyl)porphyrin,    5,10,15,20-tetrakis(2-furyl)porphyrin,    5,10,15,20-tetrakis(3-furyl)porphyrin,    5,10,15,20-tetrakis(2-mercaptophenyl)porphyrin,    5,10,15,20-tetrakis(3-mercaptophenyl)porphyrin,    5,10,15,20-tetrakis( 4 -mercaptophenyl)porphyrin,    5,10,15,20-tetrakis(2-aminophenyl)porphyrin,    5,10,15,20-tetrakis(3-aminophenyl)porphyrin,    5,10,15,20-tetrakis( 4 -aminophenyl)porphyrin,    [5,10,15-tris(2-thiofuryl)-20-mono(phenyl)]porphyrin,    [5,10,15-tris(3-thiofuryl)-20-mono(phenyl)]porphyrin,    [5,10-bis(2-thiofuryl)-15,20-di(phenyl)]porphyrin,    [5,10-bis(3-thiofuryl)-15,20-di(phenyl)]porphyrin,    [5,15-bis(2-thiofuryl)-10,20-di(phenyl)]porphyrin,    [5,15-bis(3-thiofuryl)-10,20-di(phenyl)]porphyrin,    [5-mono(2-thiofuryl)-10,15,20-tri(phenyl)]porphyrin, and    [5-mono(3-thiofuryl)-10,15,20-tri(phenyl)]porphyrin.    
     
     
         13 . The sensor according to  claim 11  or  claim 12 , wherein an electrode is used, the electrode comprising a conductive component inserted into a small tube prepared from an electrical insulating material, the outside of this small tube being covered with a material acting as a counter electrode such as a metal to form a counter electrode, a metal porphyrin polymer membrane being formed on the tip of the conductive component, and the electrode having a needle-like shape.  
     
     
         14 . The sensor according to  claim 11  or  claim 12 , wherein an electrode is used, the electrode comprising a conductive component inserted into an electrical insulating material, the electrical insulating material being placed in a counter electrode material, the resulting counter electrode material being housed in an electrical insulating material, of which the outside is coated with a material acting as a ground, a metal porphyrin polymer membrane being formed on the tip of the conductive component, and the electrode having a needle-like shape.  
     
     
         15 . The sensor according to anyone of claims  11 - 14 , used for measuring superoxide anion radicals.  
     
     
         16 . A method for detecting active oxygen species in a sample comprising measuring a current produced by oxidation-reduction reaction between a metal in a metal porphyrin polymer membrane and active oxygen species using the sensor according to any one of claims  11 - 15 .  
     
     
         17 . The method according to  claim 16 , wherein the active oxygen species to be detected are superoxide anion radicals.